Portable drill



R. D. PlTTS PORTABLE DRILL April 12, 1949.

2 Sheets-Sheet 1 Filed July 24, 1944 57 2a 23 a a 3' [NVEN TOR.

EMA 41 D P/77'J ATTORNEY R. D. PITTS PORTABLE DRILL April '12, 1949.

2 Sheets-Sheet 2 Fild July 24, 1944 INVENTOR. A EU/WLD p/T/J BY @M Alf/UP/Vt'lf v i a {J w a Patented Apr. 12, 1949 UNITED STATES OFFICE 2 Claims.

This invention relates to portable drills and has particular relation to an auxiliary structure primarily for use in conjunction with drills of the portable, electric type for greatly increasingthe range of usefulness of such devices.

A primary object of my invention is the provision of an improved portable drill having means for increasing the speed and ease of operation of such a device.

Another primary object of my invention is the provision of an auxiliary structure which may, if desired, be constructed as an integral part of an electric drill of the portable type for providing a truly portable drill press which may be readily manipulated by the operator in any position without noticeable discomfort to the operator.

A further main object of my invention is the provision of a drill press of this nature which may be operated with one hand and which may, in a preferred embodiment of my invention, be controlled and pressure applied by the grip of one hand of the operator.

A further object of my invention is the provision of means, in a device of this character, which will provide for steady and positive feeding of the drill against the work.

Other and further features and objects of my invention will be more apparent to those skilled in the art upon a consideration of the accompanying drawings and following specifications, wherein are disclosed exemplary embodiments of the invention, with the understanding, however, that such changes may be made therein as fall within the scope of the appended claims, without departing from the spirit of the invention.

In said drawings:

Figure 1 is a View in side elevation of a portable drilling device constructed in accordance with a preferred embodiment of my invention, with portions thereof broken away to better illutrate the structure.

Figure 2 is a fragmentary View in side elevation and partly in section illustrating the ratchet feeding mechanism of the drill shown in Figure 1.

Figure 3 is a fragmentary view in top elevation of the ratchet mechanism illustrated in Figure 2.

Figure 4 is a view in side elevation of an auxiliary work engaging hook for use in conjunction with the drill shown in Figure 1.

Figure 5 is a fragmentary view in top elevation of the means employed for detachably mounting the work engaging hook to the feeding mechanism.

Figure '7 is a view in side elevation of a portable drilling device constructed in accordance with another embodiment of my invention.

Figure 8 is a fragmentary view, partly in sec tion and partly in end elevation, of the device of Figure '7 as taken on the line 8-8.

Figure 9 is a fragmentary view in perspective and partly in section of the mounting and feeding mechanism of the device of Figure '7, and

Figure 10 is a fragmentary view, partly in section and in enlarged relation, illustrating the feeding and ratchet mechanism of the devices shown in Figures 7 to 9 inclusive.

Referring now to the drawings, and in particular to Figures 1 to 6 thereof inclusive:

The device in Figure 1 is illustrated as embodying an electrically powered portable drill H] of standard construction, having a pistol grip handle I l and a chuck I2 driven through reduction gearing (not shown).

The work feeding or clamping member, indicated generally at l3, hooked at its outer end, as indicated at M, to provide a work engaging portion, is provided with a toothed portion or rack on its upper edge, as shown at 16, and the entire clamping bar I3 is mounted for sliding movement, in a direction parallel to the axis of the drill, within a housing which I have indicated generally at M. This housing may be formed integral with the body of the drill H], or may be formed of heavy sheet metal or the like, as shown, to provide a slot [8 for the reception of the clamping bar and formed, as at ill, to permit its lower portion to be clamped about the body or barrel of the portable drill by means of screws 2|. The clamping bar I3 is made a snug sliding fit with in the mounting member I! and the upper and lower walls of the slot E8 of this mounting bracket are preferably provided with wear resisting slides, as at 22.

The mounting bracket H is provided with a pair of rearwardly extending ears 23, pierced at their rear-most ends to receive pivots 24 on which a feed handle 26 is pivotally mounted. This feed handle is preferably made of a heavy piece of sheet metal or the like so as to provide a pair of upright portions or lever members joined together at their lower portions to provide a rounded grip adapted to be closely engaged over the rear portion of the pistol grip handle of the drill when pressed thereagainst by the operator.

A ratchet dog or pawl, which I have indicated generally at 21, is mounted on a pivot 28 between the upwardly extending lever portions of the handle 26 and immediately above the toothed rack of the clamping bar. The structure of this ratchet mechanism is best illustrated in Figures 2 and 3. The pawl 27 is preferably provided with a relatively long arm 29 for engagement with the forward sides of the tooth members l6 and it will now be understood that when the clamping bar is engaged over the work to be drilled, the pistol grip H and the feed handle 26 may be gripped by the operator and forced slowly together. The pawl 2! is engaged against the forward surfaces of the ratchet teeth and will move the clamping bar rearwardly within the supporting housing so as to draw the hooked portion l4 and thus the work firmly against the rotating drill.

The force applied to the pistol grip is of course multiplied and the rate of feed of the drill against the work is readily controlled due to the relative leng of the ever a p de n the andle 26 by the relative spacing of the pivot members and he han e 2 is bi sed a o the handle it of the drill by means of torsion spring-r31! disposed about one of the pivots 2E.

the drill point enters the material being drilled and thefeedhandle 28 reaches the end of its stroke and comes to bear against the pistol grip handle l I, it may be released and the spring 3|; will again force it rearwardly. The pawl 27 will, of; course, bemoved forwardly and will engage a new toothand the handle 26 may immediately be forced-forwardly tofeed the drill point still further into the work.

The forward end of the pawl 21 is provided with a tooth engaging portion 32 which is adapted to be moved into engagementwith the rear surface of; a ratchet tooth for holding the clamping bar 13 in extended position, as in Figure 1, against the tension of the coil spring 33. Thisspring 33 is. employed merely to hold the clamping bar in engagement with the work when the feed handle 26*is released after the end of a stroke.

The pawl 27 may be moved by means of the thumb lever 33' to engage either th rear tooth 29 or the forward tooth 32 with the teeth of the rack and is resiliently held in either operating position by means of a leaf spring 34, which is disposed between a notch 36 in the upper surface of the pawl 21 and the inwardly extending upper ends of: the handle member 3?. Th notch 36 isso positioned in the pawlthat it willbe in dead center position or in line with the pivot 28 and theupper mounting point 37 of the spring 34 whenboth tooth portions 29 and. 32 of the dogare disengaged from the teeth of the rack. Thus it will be seen that when the pawl is placed in either forward or reversed positions the notch 3.6:will' be oil-center and the spring. will holdthe pawl in position.

It may .be understood that other means than the spring 33 may be employed for holding the clamping. bar in engagement with the work when thefeed handle 25 is released for a new stroke. Theclamping bar i3; for example, may be made a--sn ug sliding fit within the guide bracket ll so as to hold the clamping bar in position by frictional engagement alone. The spring 33 and the forwardtogth 32 of the dog may thus be dispensed with. If desired, a ratchet pawl, independent of the pawl Zl, may beemployed adjacent, the upper dsee the sl t .8 t en e t a and pr t releasinse t e am in ba u on ease of the te an i e=2a ir eierable that the. hook or work en ag n 4 portion I 4 of the clamping bar be made interchangeable as indicated at 4| and as best illustrated in Figure 5. The forward end of the clamping bar is bifurcated, as at 42, to receive the end of the hook member I 4 and the two members are secured together by means of bolts 43.

Auxiliary hook members may thus be employed, and I have shown one of these auxiliary hook members at 44 in Figure 4 which hook is provided with a deeper throat to proyidef or drilling holes at greater distances from the edges of the work than the device of Figure 1 is capable of doing.

In the modified form of my invention illustrated in Figures 7 to 10 inclusive I have shown a structure somewhat better adapted to larger sizes of portable electric drills. The drill 5| is provided with a mounting pad 52 on which a handle may be mounted. This handle, which I have indicated generally at 53, embodies a body po t n i hav n a. s t. extendinalongitudisallr th reinr ueh a. dir ction parallel. t9 ax o th dr l. fort e re ept on of e c amp: s: bar 1 T i damn n baris preferablyproe vided upper and lower sliding ed-gess5l. and 58 for free sliding movement within the, slot, 55. The clamp ng is o i led- Wi h. a work-em gaging hook. 59 as previously described. and the bar is also provided with a toothedportion; 6| alongthe lower edge thereof.

The feed; handle 62: is preferably. .pivotally mounted at its upper end on a pair of ears extendfe war ly from. the. body portion. of the ha d e and as hown t 63.

The ratchet mechanism, which. is indicated at 65A; is best shown in Figure lfl. This. member is pivotally mounted in the handle, as at 66, and pro id d wit to thed portions 6 and 6.8. on .01 posite sides thereof and a thumb lever B 9, .aspre: v ous vdescribed, in connection, with F u Thaspring l l, which is located. within the handle 5.2, is formed so as to direct its force. toward-the pivot 56 and thus selectively holdtooth 61 011.58 in engagement when the pawlis once .movedto offecenter position.

If desired, the clamping bar 155: may bebuiltof three laminations of strap-ironor the like riveted or welded into one unit, as is. shown. in Figures 8 and. 9, with the center member. 5511.- extending outwardly along one edge frombetween the outer guide members 56b-to provide for the toothed portion ill and also to provide for a recess along the. opposite edge for the receptionv of a tension spring 72. This. spring may 'be secured at its forward end lfito the clamping: bar,.as indicated in Figure '7, and'at its rearward end totherear edge of the handle body 54%, as indicated at 14.

A brace 35 may be mounted between therearwardly extending portion of the body .of the .handie and the rear endof the .dr-il-l'bl.

I have devised a portable drilling. devicewhich may be readily manipulated. by. an. operator by the use of one hand only, when. necessary, and

The drilling of a relatively few holes of any depth in metal is usually quite tiring to the operator, whereas with a device such as I have herein described, it is possible to drill large numbers of holes without noticeably tiring the operator and it is possible to drill these holes in considerably less time than would be required when using an ordinary portable electric drill.

Furthermore, in a device constructed in accordance with my invention, the drill point requires sharpening much less frequently since the point of the drill is not permitted to merely slide over the surface of the work and thus burn or become smooth and dull. The drill is held in firm contact with the work and, in addition to this, there is less tendency toward the breaking of drills since the weight of the drill is generally transferred to the clamping bar.

Although I have shown and described specific embodiments of my invention, it is apparent that modifications thereof may be made. For example, the toothed rack for clamping the bar may be mounted, relative to the body of the drill, in other positions and by other means than those shown, The toothed rack may be placed on the opposite side of the clamping bar and the pawl mechanism on the feed handle placed in a different relative position with respect to the pivot point of the feed handle. The guide mechanism for the clamping bar may, if desired, be made integral with the body of the drill. Furthermore, portable drills of extremely large size may be provided with a pair of feed mechanisms or a single feeding mechanism with a pair of feed handles so as to permit the operator to use both hands in feeding the drill into the work. These and other modifications may be made without departing from the spirit and scope of my invention as set forth in the appended claims.

I claim as my invention:

1. In combination with a portable drill having rotatable drilling means and a fixed handle adapted for the manual support of said drill, an auxiliary feed mechanism therefor including a guide member having a guide slot extending longitudinally therethrough, means for attaching the said guide member to the portable drill with the slot thereof extending substantially parallel with the axis of the drilling means, a clamping bar extending through said guide slot, hooklike work engaging means operatively secured to one end of said clamping bar, the said clamping bar having ratchet teeth on one side thereof, an operating handle disposed adjacent the fixed handle of the portable drill and movable relative thereto, and pawl means for operatively connecting the said operating handle and said ratchet tooth portion of the clamping bar the said operating handle and fixed handle adapted to be both received in an operators hand and forced together by gripping action of the operators hand, the said connecting means being so arranged as to force the said work engaging means toward the said drilling means when said handles are forced together.

2. In combination with a drilling mechanism, means for biasing work to be drilled, toward the said drilling mechanism and in a direction parallel with the axis thereof, a supporting handle for manual support of said drilling mechanism, a feeding handle pivotally mounted near one end thereof in close proximity to said supporting handle and mounted for movement relative thereto, and means including a rack on the biasing means and a dog on the feeding handle spaced from the point of pivotal attachment of the said feeding handle for converting movement of said feeding handle into movement of the biasing means toward the drilling mechanism when the feeding handle is forced toward the supporting handle by the gripping pressure of the hand of the operator about both of said members.

ROBERT DONALD PITTS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 55,696 Nevergold et a1 June 19, 1865 874,090 Leeland Dec. 17, 1907 975,031 Greene i Nov. 8, 1910 2,180,5978 Crewe Nov. 21, 1939 2,373,785 Seaboly Apr. 17, 1945 FOREIGN PATENTS Number Country Date 20,600 Great Britain Sept. 1, 1894 

